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Tracks and double partons

Tracks and double partons. Lee Pondrom 31 October 2011. Jet 20 data. Use tracks to look at two vertices Use Rick Field’s averages to characterize the track patterns. Jet20 data two vertices. Jet20 data two vertices. Cuts to the data. E T jet1>15 GeV |Zvtx1-Zvtx2|>10 cm

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Tracks and double partons

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  1. Tracks and double partons Lee Pondrom 31 October 2011

  2. Jet 20 data • Use tracks to look at two vertices • Use Rick Field’s averages to characterize the track patterns.

  3. Jet20 data two vertices

  4. Jet20 data two vertices

  5. Cuts to the data • ET jet1>15 GeV • |Zvtx1-Zvtx2|>10 cm • |trkvtx-Zvtx|<1 cm • Track pT>.5 GeV • |track η|<1 and |jet η|<1 both jets. • For Rick’s ‘transverse track’ requirement, use jet1 to define the Δφ region.

  6. Rick Fields definitions CDF Run 1 Analysis Charged Particle Df Correlations PT > PTmin |h| < hcut Leading Calorimeter Jet or Leading Charged Particle Jet or Leading Charged Particle or Z-Boson “Transverse” region very sensitive to the “underlying event”! • Look at charged particle correlations in the azimuthal angle Df relative to a leading object (i.e. CaloJet#1, ChgJet#1, PTmax, Z-boson). For CDF PTmin = 0.5 GeV/c hcut = 1. • Define |Df| < 60o as “Toward”, 60o < |Df| < 120o as “Transverse”, and |Df| > 120o as “Away”. • All three regions have the same area in h-f space, Dh×Df = 2hcut×120o = 2hcut×2p/3. Construct densities by dividing by the area in h-f space.

  7. Dijet energies and φ correlation

  8. Track multiplicity and sum pT

  9. Jet20 data compared to Pythia

  10. Jet20 data compared to Pythia

  11. Jet20 data trigger vertex tracks compared to second vertex tracks

  12. Jet20 data compared to Pythia on the main vertex

  13. Jet20 data compared to Pythiaon the secondary vertex

  14. Comparison of transverse N and ∑pT RField, Jet20 data, and Pythia • Leading ‘jet’ ET=28 GeV • RField Jet20 data Pythia • trig vtx trig vtx 2ndvtx trig vtx 2ndvtx • N 0.6 .61±.01 .48±.01 .53±.01 .44±.02 • ∑pT 0.7 .72±.01 .46±.01 .69±.01 .41±.02 • pTmax 1.6 1.66±.02 .97±.03 1.53±.03 .92±.03 • pT in GeV, errors are statistical only. Field’s numbers are read from slides 7,8, and 9.

  15. The ‘away’ jet • Rick’s slide 10 shows away jet <N> =1.4 • Jet20 data away jet <N>=1.8±.02 (stat) • Jet20 Pythia away jet <N>=2.1±.04 (stat). • So there seems to be more track activity in jet20 than for comparable ET opposite a Z

  16. Conclusions • Jet20 data may be slightly more active than Pythia is. But the agreement is good on each of the two vertices. • The trigger vertex with the 20 GeV ET jets has more track activity in the transverse region than does the second vertex. • Each track activity is non-perturbative.

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